Borussia Dortmund, a German football team was on its way to a quarterfinal match against Monaco when three explosive devices went off by the side of the bus on Tuesday night, injuring one player.

The explosion occurred at about 7.15pm local time in Dortmund’s Höchstem district, approximately six miles (10km) from the club’s stadium.

Police confirmed that the explosion broke some of the vehicle’s windows. Defender Marc Bartra was injured by glass shards and was taken to the hospital. Barta will undergo surgery on his injured arm for the fracture to remove shrapnel.

Goalkeeper Roman Bürki said that he was sitting in the back row next to Bartra. After the explosion, everyone in the bus got their heads down. They don’t know if there would be more explosions. The police arrived quickly, sealed everything off. Everyone was all in shock.

A spokesman later said, they are treating the incident as a targeted attack on the Borussia Dortmund’s team. An undetonated device was found in the vicinity of the team hotel.

Police discovered a letter near the scene of the crime which contains a claim of responsibility for the attack and was trying to authenticate it.

Hans-Joachim Watzke, Borussia Dortmund’s chief executive said, the explosive devices were hidden behind a hedge near the hotel where the team was staying.

Even if the team is in complete shock, they still need to process this experience because another match will be taking place in less than 24 hours, Watzke added.

The club confirmed the quarter-final has been postponed until Wednesday. Tuesday night’s other match between clubs Barcelona and Juventus already went ahead.

Police and Borussia Dortmund officials assured the supporters, the team was not under any threat once inside the stadium and that everyone should stay calm while leaving.